1. Field of the Invention
The invention relates to a backlight module and a lighting keyboard, and more particularly, to a backlight module and lighting keyboard utilizing a reflective layer to enhance lighting efficiency.
2. Description of the Prior Art
Recently, many information processing devices, such as, notebook computers, personal digital assistants (PDAs) and so on, have been developed as technology progresses in the variety of surroundings. For example, in a dark place users may not see numbers or characters marked on a keyboard. Therefore, it causes difficulty in reading. Even worse, users' vision might be impaired due to difficult reading. Lighting keyboards are available on the market for improving above problems. Besides, various disposals of light sources increase artistic feeling of the lighting keyboards, so as to increase market value.
A lighting keyboard is a non-spontaneous lighting device, so a backlight module is taken as a light source. Please refer to FIG. 1. FIG. 1 is a cross-sectional diagram illustrating a conventional lighting keyboard 1. As shown in FIG. 1, the lighting keyboard 1 includes a keyboard module 10 and a backlight module 12, and the keyboard module 10 is disposed on the backlight module 12. The backlight module 12 includes a light source 120 disposed in a light guiding plate 122, and the light source 120 emits light to the light guiding plate 122. A reflective component 124 disposed under the light guiding plate 122 reflects the light emitted through the light guiding plate 122 toward the keyboard module 10. Afterward, the light passes through the light guiding plate 122 and a predetermined position of the keyboard module 10, such as a transparent area on a keycap, so that users can see light projecting from the lighting keyboard 1.
Besides the transparent area on the keycap capable of being penetrated by light, some gaps are existed in original design of the keyboard module 10, such as some gaps between keyswitches . Therefore, light projected out of the light guiding plate 122 may be emitted through some unexpected positions to cause unexpected lighting effect. The unexpected lighting effect can be prevented by a masking of a backlight module. As shown in FIG. 1, a masking 126 is disposed between the light guiding plate 122 of the backlight module 12 and the keyboard module 10. The masking 126 has an opening 1260 (or a transparent area) . When light is projected to the masking 126 from the light guiding plate 122, part of light is emitted through the opening 1260 to the keyboard module 10, and part of light is absorbed by the masking 126. Light is emitted out of some specific positions by the opening 1260 for preventing the unexpected lighting effect.
However, light mostly is absorbed by the masking. Therefore, lighting efficiency of the light source is not good. In order to maintain sufficient brightness, more light sources or light sources with higher brightness are required, so as to increase production cost of the backlight module and the keyboard.